Is all the information that is available via Windows Management Instrumentation Command-line(wmic) also available via Windows registry(regedit)?
What are the main differences between them?
WMIC is an interface to WMI. WMI and the Registry serve similar purposes in different ways. The registry has been around for considerably longer than WMI. Both provide both system and application specific information, but due to adoption levels, WMI has considerably more system information than application information. Some of the information can be found in both, but nowhere near all. I would also add that while there are much easier ways to do it, you can technically get to the data in the registry via WMI while the reverse is not true.
One more significant difference between WMI and the registry is that WMI is much more than just a data source. It also acts as an interface to the Operating System. It exposes methods to both return data dynamically and to accomplish various tasks. For instance WMI can be used directly to create a new process.
The registry is a database of all Windows' settings.
WMIC is the command-line interface to control Windows Management Instrumentation.
Since this is also relevant:
In other words, it is very similar in function to SNMP: Network management.